A body structure for vehicles such as automobiles, designed to increase the rigidity of a floor panel portion is disclosed, for example, in Japanese Patent Laid-Open Publication No. 5-221342. The disclosed vehicle body structure will be described with reference to FIGS. 12 and 13 hereof.
Referring to FIGS. 12 and 13, a vehicle 200 has a body 201 with a floor panel 204. The floor panel 204 has a floor tunnel 202 bulged toward a passenger compartment at a transversal center and extending longitudinally of the body. To the underside of the floor panel 204, a pair of left and right floor frame members 203, 203 extending longitudinally on the opposite sides of the floor tunnel 202 are joined. In the floor panel 204, a number of beads 205 extending transversely are formed at longitudinal regular intervals. The beads 205 intersect the left and right floor frame members 203, 203.
As shown in FIG. 13, when an impact energy En acts from the front on a front portion of the floor panel 204 at a transversely outer position, that is, at an offset impact on the front of the body 201, the impact energy En acts on the front end of one of the floor frame members 203. The impact energy En is dispersed and transmitted from the floor frame member 203 into the corresponding one of the left and right sides of the floor panel 204, and also transmitted to the floor tunnel 202.
At an offset collision, an impact energy En is greater on one of the right and left sides. As compared with that at a frontal crash, an impact energy En acting on one of the floor frame members 203 is much greater. The impact energy En transmitted from the floor frame member 203 to the floor panel 204 is also greater. When the great impact energy En causes the floor frame member 203 to retreat, the floor panel 204 deforms rearward from the floor tunnel 202 of relatively high rigidity.
Against this, the portion of the floor panel 204 in which the beads 205 intersect the floor frame member 203 has great rigidity, but the other portion has small rigidity. The floor panel 204 largely deforms in the low-rigidity portion (, forming large creases, for example), affecting the amount of retreat of the floor frame member 203 joined to the floor panel 204, and affecting the state of the joint between the floor panel 204 and the floor frame member 203. In order to limit these effects, it may be conceivable to reinforce the low-rigidity portion with a reinforcing material. This, however, would make the body structure complicated, increasing the weight of the body, and leaving room for improvement.
The present invention provides a vehicle body structure with a simple configuration capable of increasing the rigidity of a floor panel against an impact energy at an offset collision.